Process characterization and mechanism for laser-induced chemical vapor deposition of a-Si:H from SiH4

TLDR: In this article, the dependence of a-Si∶H film deposition by laser-induced decomposition of SiH4 on the different process variables is studied, and the gas phase temperature in the beam center, produced by CO2 laser irradiation in parallel configuration, is estimated using a simple energy balance model.

Abstract: The dependence of a-Si∶H film deposition by laser-induced decomposition of SiH4 on the different process variables is studied. The gas phase temperature in the beam center, produced by CO2 laser irradiation in parallel configuration, is estimated using a simple energy balance model. The surface temperature is measured with high accuracy employing a Ni sensor (250°–400 °C). The deposition rate and film properties such as the hydrogen content and the optical energy gap are determined as a function of these parameters. The production of H2 (≈10%), Si2H6 (≈2%), and Si3H8 in the gas phase during laser irradiation is proved by a mass spectrometric analysis. The chemical reaction processes induced in the gas phase and at the surface are discussed. A mechanism explaining the main features of the complicated chemistry involved is developed.